Animating smoothing uncertainty in a GAM

mgcv-posterior-animate.R

# devtools::install_github("thomasp85/transformr")
# devtools::install_github("thomasp85/gganimate")

library(tidyverse)
library(gganimate)
library(rstanarm)

theme_set(theme_grey())

# Get the mpg value to predict over
newdat <- data.frame(
  mpg = seq(min(mtcars$mpg), max(mtcars$mpg), length.out = 100))

m <- stan_gamm4(
  hp ~ s(mpg),
  data = mtcars,
  chains = 1,
  iter = 2000)


demo_lines <- tidybayes::add_fitted_draws(newdat, m, n = 20)
interval <- tidybayes::add_fitted_draws(newdat, m) %>%
  tidybayes::median_qi()


# Plot with animation!
ggplot(demo_lines, aes(x = mpg)) +
  geom_ribbon(
    aes(ymin = .lower, ymax = .upper),
    data = interval,
    fill = "lightgrey",
    col = NA) +
  geom_point(aes(y = hp), data = mtcars) +
  geom_line(
    aes(y = .value),
    data = demo_lines,
    col = "blue") +
  transition_states(.draw, 1, 1)